PROCESS FOR MAKING COPOLYMERS OF MALEIC ANHYDRIDE AND A C1 -C4 ALKYL VINYL ETHER HAVING A HIGH SPECIFIC VISCOSITY

2083951 9202564 PCTABS00010 What is described herein is a process for making a copolymer of high specific viscosity by polymerisation of maleic anhydride and a C1-C4 alkyl vinyl ether monomer. The invention involves polymerizing said monomers to form a slurry of said copolymer in excess alkyl vinyl ether as solvent and toluene or an aliphatic organic compound as cosolvent, and is characterized by the steps of: (a) precharging a reactor with C1-C4 alkyl vinyl ether as solvent at a reaction temperature, (b) feeding a mixture of maleic anhydride and a C1-C4 alkyl vinyl ether in substantially stoichiometric amounts, preferably with a slight excess of the alkyl vinyl ether, and at a selected rate, into said precharged reactor, and (c) simultaneously feeding a predetermined mixture of toluene or an aliphatic organic compound and a polymerization initiator continuously over substantially the entire period of polymerization.